High velocity web floating air bar having an internal passage for transverse air discharge slot means

Abstract

An elongated and generally tubular air bar having pressurized air discharge slot means extending transversely across a web to be floated by the bar, the bar having an internal air delivery passage communicating with the transverse slot means. The interior of the air bar is supplied with pressurized air which first enters the internal passage before it is delivered to the discharge slot means whereby a tortuous path is provided for the air and through which the pressurized air must pass before being discharged by the slot means against the web, thereby cross machine momentum components of air flow are dissipated before the air is discharged by the slot means against the web and uniform drying of the web in a cross machine direction is assured.

I claim: 
     
       1. An elongated air bar assembly for being positioned transversely of and adjacent to a running web for supporting said web on a cushion of air, said elongated assembly comprising, an outer side adapted to be positioned closely adjacent said web, an inner side having means communicating with an air supply, and two opposite and spaced apart side walls which together with said outer and inner sides define a pressurizable central chamber into which pressurized air is conducted, an air discharge slot located along said outer side, said slot being defined by said outer side and one of said side walls, and inner wall means located along and adjacent to, but spaced inwardly from said one of said side walls, said inner wall means extending generally coextensive in size with said one of said side walls to thereby define therewith an air delivering passageway to said slot, said passageway being in air receiving communication at a location generally adjacent said inner side and with said central chamber for receiving pressurized air from said central chamber, whereby the air entering said central chamber then enters said passageway for discharge through said slot for impingement against said web. 
     
     
       2. An elongated air bar assembly for being positioned transversely of and adjacent to a running web for supporting said web on a cushion of air, said elongated assembly comprising, an outer side adapted to be positioned closely adjacent said web, an inner side having means communicating with an air supply, and two opposite and spaced apart side walls which together with said outer and inner sides define a pressurizable central chamber into which pressurized air is conducted, an air discharge slot located along each longitudinal edge of said outer side, said slots being defined by said outer side and said side walls, said inner wall means located along and adjacent to, but spaced inwardly from said side walls, said inner walls extending generally coextensive in size with said side walls to thereby define therewith air delivering passageways to said slots, said passageways being in air receiving communication at a location generally adajcent said inner side and with said central chamber for receiving pressurized air from said central chamber, whereby the air entering said central chamber then enters said passageways for discharge through said slots for impingement against said web. 
     
     
       3. The assembly set forth in claim 2 including an elongated, generally U-shaped member having a pair of walls and a bight portion between said walls, said walls constituting said inner wall means, and said bight portion positioned generally along said outer side. 
     
     
       4. The assembly set forth in claim 3 including means for removably attaching said U-shaped member in said assembly. 
     
     
       5. An elongated and generally tubular air bar adapted to be positioned closely adjacent a running web for supporting said web, said air bar including two side walls and an outer side therebetween, said air bar defining a pressurizable central chamber into which pressurized air is conducted and having means communicating with a pressurized air supply, said bar having air discharge slot means located adjacent and along said outer side and for discharging air against said web, an elongated, generally U-shaped member having a pair of walls and a bight portion between said walls, said bight portion positioned generally along said outer side, and an air deliverying passageway in said bar and communicating with said slot means and also in air receiving communication with said central chamber for receiving pressurized air therefrom, said U-shaped member together with said side walls defining said passageway whereby pressurized air in said central chamber enters said passageway for discharge through said slot means for impingement against said web. 
     
     
       6. The assembly set forth in claim 5 including a single wall insert secured in said bar and defining therewith said passageway.